Stainless Steel Instead of Gold

New German-Chinese Research Project at the Institute of Materials Research

The Department of Hybrid Material Systems at the Helmholtz-Zentrum Geesthacht (HZG) was successful in securing joint funding from the Helmholtz Society and the Chinese Academy of Sciences (CAS). Twenty-three applications were submitted in all, of which five were chosen for funding with a Helmholtz-China Joint Research Group (HCJRG).

Nanoporous Gold: Clearly identify the sponge-like structure.

The program funds projects in which outstanding German and Chinese researchers work in close cooperation. It provides joint funding for a period of three years. The Helmholtz Society is financing the project with 120,000 Euros per year from its Initiative and Networking Fund. The Chinese Academy of Sciences will support the projects with up to 35,000 Euros per year.

The German team working on the project “Nanoporous transition metals for strength and function - towards a cost efficient materials base” will be lead by physicist Dr. Jürgen Markmann (HZG) and Professor Jörg Weißmüller (HZG and the Technical University Hamburg-Harburg, TUHH). Professor Hai-Jun Jin (Shenyang, National Laboratory for Materials Science) is playing a leading role in China. The joint project will further intensify cooperation in the Hamburg region between the HZG and the TUHH: two new positions for doctoral candidates in Geesthacht and at the TUHH can now be created thanks to the funding.

Certain structural and functional properties are found in nanoporous gold. The aim of the new project is to study these properties in other metallic materials. Available high purity gold is insensitive to most impurities and is therefore used as a model material to study the properties of nanoporous structures. Dr. Jürgen Markmann explains: “Now the question arises, how can the methods for structural formation and surface behaviour be transferred to economically more relevant metals, such as stainless steel, aluminium or titanium.”

In the Department of Hybrid Material Systems, under the direction of Professor Jörg Weißmüller, nanoporous gold has been studied for quite a long time. The scientists only recently discovered that the saturation of nanoporous gold with a fluid can be switched on and off by using electrical modifications of the surface tension. By applying small electric control voltages to the metal sponge, the fluid absorption can be accelerated, slowed or stopped entirely.

Other functional aspects, such as modifying the surface tension using mechanical stress, make future application in the form of robust and planar sensors conceivable. For this purpose, the nanoporous metallic coatings would be applied to automobiles or aircraft and information on the condition of the coated component could be delivered using electrical signals. The economical material alternatives to gold are the crucial factor in the viability of such technology in the future.